Multi-chip module with multiple compartments

ABSTRACT

The present invention provides a multi-chip module having multiple compartments. Circuitry is arranged on a substrate in such a manner that circuit components requiring specific operating environments are located in discrete areas dedicated to accommodate the circuit components. A cover, having multiple chambers that align with the discrete areas on the substrate, is secured to the substrate to define the multiple compartments. The compartments are separated by material that effectively isolates the compartments relative to one another.

This is a division of application Ser. No. 07/913,100, filed on Jul. 14,1992 now U.S. Pat. No. 5,369,552.

FIELD OF THE INVENTION

The present invention relates to the arrangement of integrated circuitcomponents on a Multi-Chip Module.

BACKGROUND OF THE INVENTION

Those skilled in the art of integrated circuits will recognize thebenefits of maximizing the number of components on a single Multi-ChipModule (MCM). For example, the components on a Multi-Chip Moduletypically require less space and operate more quickly than theirconventional counterparts. However, those skilled in the art will alsorecognize that some components require operating environments that areincompatible with the operating requirements of other components. Forexample, an oscillator should be maintained at constant elevatedtemperature to maintain accuracy, while circuitry with high powerconsumption should be cooled. Similarly, some components may requireisolation from noise, electricity, electromagnetic interference (EMI),electrostatic interference and/or radiation, which may emanate fromother components. Accordingly, a need exists for effectively isolatingvarious components on a Multi-Chip Module.

SUMMARY OF THE INVENTION

According to one embodiment, the present invention provides a multi-chipmodule having multiple compartments. Circuitry is arranged on asubstrate in such a manner that circuit components requiring specificoperating environments are located in discrete areas dedicated toaccommodate the circuit components. A cover, having multiple chambersthat align with the discrete areas on the substrate, is secured to thesubstrate to define the multiple compartments. The compartments areseparated by material that effectively insolates the compartmentsrelative to one another.

According to another embodiment, the present invention provides a coverfor a substrate bearing multiple integrated circuit components as wellas discrete circuit components such as resistors, capacitors, inductors,transistors and diodes. The cover includes a peripheral wall, a top, andan interior wall. The top abuts the peripheral wall to define acontainment space. The interior wall extends between discrete portionsof the peripheral wall to divide the containment space into multiplechambers. The chambers align with the components on the substrate toeffectively isolate a first component relative to a second component.Ideally, the interior wall effectively isolates against the transfer ofheat, electricity, noise, electromagnetic interference, electrostaticinterference and radiation, and it is integrally joined to theperipheral wall and the top. The top should similarly isolate theenclosed components from each other as well as external interferences,the portion of the top over each compartment having the same isolatingcharacteristics as the walls for the compartment.

According to another embodiment, the present invention provides amulti-chip module having a housing that includes a first compartment anda second compartment. The first compartment is effectivelyenvironmentally isolated relative to the second compartment. A firstcomponent or group of components having a first set of operatingparameters is positioned within the first compartment. A secondcomponent or group of components having a second set of operatingparameters, which is incompatible with the first set of operatingparameters, is positioned within the second compartment. The housingincludes a substrate, which supports the first component and the secondcomponent, and a cover having a first chamber and a second chamber. Thesubstrate is connected to the cover to effectively seal the firstchamber relative to the second chamber, thereby defining the firstcompartment and the second compartment therebetween.

According to another embodiment, the present invention provides amulti-chip module having an effectively isolating partition betweenotherwise disruptive components. Additionally, the present inventionprovides a multi-chip module having circuitry arranged in such a mannerthat circuit components requiring specific operating environments arelocated in discrete areas dedicated to accommodate the components.Similarly, the present invention provides a method of making amulti-chip module that includes the step of arranging the componentswithin the module in such a manner that circuit components requiringspecific operating environments are located in discrete areas dedicatedto accommodate the components.

The advantages of the present invention will become apparent to thoseskilled in the art upon a more detailed description of a preferredembodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring to the Figures, wherein like numerals represent like partsthroughout the several views:

FIG. 1 is a perspective view of a multi-chip module constructedaccording to the principles of the present invention, showing its coverremoved from its substrate;

FIG. 2a is a top view of the cover shown in FIG. 1;

FIG. 2b is a bottom view of the cover shown in FIG. 1;

FIG. 3 is a top view of a substrate similar to that shown in FIG. 1;

FIG. 4 is a top view of the multi-chip module shown in FIG. 1 with aportion of the cover broken away; and

FIG. 5 is a perspective view of a portion of a printed circuit board onwhich is mounted the multi-chip module shown in FIG. 1.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

For purposes of describing the present invention, a multi-chip module isdefined as any advanced semiconductor substrate which provides aninterconnect path between electrical components. In FIG. 1, a preferredembodiment of a multi-chip module (MCM) constructed according to theprinciples of the present invention is designated at 100. The MCM 100includes a cover 200 and a substrate 300, which interconnect to define ahousing 123 (as shown in FIG. 4). Circuit component areas 310, 320, and330, each including one or more integrated circuits or other discretecircuit components, are designated on the substrate 300 and residewithin the housing 123. Once assembled, the MCM 100 is suitable formounting to a printed circuit board 99 (as shown in FIG. 5) forinclusion in a computer or other electronic system. Mounting to theprinted circuit board can be realized with pin grid socket, surfacemount, or through-hole techniques, depending upon the multichip moduledesign.

As shown in FIG. 2a, the cover 200 includes a top 250 that abuts aperipheral wall 240 to define a containment space 245. As shown in FIG.2b, an interior wall or partition 213 extends between discrete portionsof the peripheral wall 240 to divide the containment space 245 intomultiple chambers or cavities. The first chamber is designated as 210,and the second chamber is subdivided by a second interior wall 223 intochambers 220 and 230. In a preferred embodiment, the peripheral wall240, the top 250, and the interior walls 213 and 223 are integrallyjoined to one another to comprise the cover 200. Peripheral wall 240 andtop 250 provide an insulating/isothermal barrier between chambers 210,220 and 230 and the external environment., while interier walls 213 and223 provide insulating/isothermal barriers between adjacent chambers.

Those skilled in the art will recognize that the arrangement ofcircuitry on a multi-chip module will vary according to eachapplication. With the foregoing in mind, the present invention will bedescribed with reference to FIG. 3, which shows a substrate 300'supporting a first component block 310', a second component block 320',and a third component block 330'. The first component block 310'includes at least one circuit component and does not require a special(or dedicated) operating environment. The second component block 320'includes at least one circuit component and requires above normal (HOT)temperatures for reliable operation of the component(s). The thirdcomponent block 330' includes at least one circuit component andrequires below normal (COLD) temperatures for reliable operation of thecomponent(s). Accordingly, the component blocks are arranged on thesubstrate 300' in such a manner that the HOT and COLD components 320'and 330', respectively, are isolated from the other components 310', aswell as from one another.

The components described above are attached to the substrate byflip-chip or flip-tab methodologies, thereby allowing the backside ofthe components to be in contact with the module cover via a thermalgrease. Heating or cooling is applied to a given area through thisbackside contact and through the use of known methods of heating andcooling such as Peltier cooling or water cooling/heating.

Heating can be accomplished through the inclusion of a power dissipatingdevice such as a resistor within the compartment to be heated. Thevoltage or current to this device would be regulated by a thermostaticcontrol circuit, a thermistor or bi-metallic device functioning as atemperature sensing element. An alternative method for heating a chamberwould be to use the power being dissipated by the circuitry enclosedwithin the compartment and using a cooling device to limit the uppertemperature excursion.

Cooling of a compartment can be affectuated through the use of a Peltierdevice. This device cools the component to which it is attached when acurrent is passed through the device. Several components can be cooledby thermally connecting the components to a thermal pad on the substrateto which the Peltier device is also attached.

Alternatively, one or more of the component blocks could be dedicated tointegrated circuit components having potentially disruptive operatingcharacteristics. For example, certain components may not require a HOTenvironment, but they may radiate sufficient heat to disrupt theoperation of other components, and thus, they may similarly requireisolation. Additionally, certain components may require isolationagainst the transfer of electricity, noise, and/or radiation, as well.

In any event, components 310, 320, and 330 are arranged on the substrate300 in such a manner that circuit components requiring specificoperating environments are located in discrete areas dedicated toaccommodate the components. The chambers 210, 220, and 230 of the cover200 align with the components 310, 320, and 330, respectively, on thesubstrate 300. The cover 200 is secured to the substrate 300 toeffectively seal the chambers 210, 220, and 230 relative to one anotherand define multiple compartments therebetween. As shown in FIG. 4, afirst compartment 110 effectively environmentally isolates the firstcomponent 310; a second compartment 120 effectively environmentallyisolates the second component 320; and a third compartment 130effectively environmentally isolates the third component 330.

The composition of the walls (interior and peripheral) is simply afunction of the requirements of the components on a given MCM. In otherwords, the walls are selectively made of materials known to effectivelyisolate against the transfer of heat, electricity, noise, radiation, etc. . . The term "effectively isolate" implies that the wall materialprovides isolation sufficient to maintain the necessary operatingconditions for the component(s) in question. Accordingly, the MCM 100may be said to have an effectively isolating partition between otherwisedisruptive components.

It can thus be seen from the above description, the the presentinvention provides a methodology whereby several circuit componentshaving differing heating, cooling or isolation requirements may bemounted on the same module. For example, a highly accurate crystaloscillator requiring maintenance at an elevated temperature may bemounted unto a single module including a microprocessor requiringcooling and having RF and IF sections requiring electromagneticisolation. The benefits to be gained from the present invention includeincreased miniaturization of computer and electronic devices as fewermodules will be required to implement a design. Increased reliability,decreased costs and decreased manufacturing time will also result from

Those skilled in the art will recognize that the preceding descriptionof a preferred embodiment was merely for purposes of illustration andexplanation. Those skilled in the art will also recognize a variety ofapplications and modifications to the present invention that fall withinthe scope of the present invention. For example, the number ofcompartments, the arrangement of compartments, and the number ofcomponents in a given compartment will vary according to specificapplications. Also, all of the components having a specific set ofoperating parameters need not be located in a single compartment.Accordingly, the present invention is to be limited only by the appendedclaims.

What is claimed is:
 1. A method of making a multi-chip module, includingthe step ofarranging the components within the module in such a mannerthat circuit components requiring specific thermal environments arelocated in discrete areas dedicated to accommodate the components.
 2. Amethod for heating specific components on a multichip module, the stepscomprising:arranging the components within the module in such a mannerthat said specific components requiring heating are located in adiscrete area within said module; enclosing said specific componentswithin a cover, thereby forming a chamber including said specificcomponents and thermally isolating said specific components from theother components within said multichip module; and heating said chamber.3. A method for cooling specific components on a multichip module, thesteps comprising:arranging the components within the module in such amanner that said specific components requiring cooling are located in adiscrete area within said module; enclosing said specific componentswithin a cover, thereby forming a chamber including said specificcomponents and thermally isolating said specific components from theother components within said multichip module; and cooling said chamber.